Originally Posted by Mike Benvo
Nothing against you either. I was simply curious since I have had thoughts of supercharging my own car. I appreciate everything you've said other than "heading back to the drawing board". The fueling is TARGET based period, that's why we have wideband o2 sensors. You can see some fluctuations in AFR but this is likely due to Fuel Factor table changes, not the lambda aim targets. You obviously don't want me in this thread, so lets agree to disagree. I have done an insane amount of development on this ECU and know exactly how it works.
You are basically saying that there are fuel compensation maps for temperature in the MSS60 DME. What side of the ECU are these on? This is my last post here, maybe Sal can chime in since I apparently have no idea what I'm talking about.
Love it when you get all technical!
Serious note - you are completely correct here with respect to the fuel factor table and lambda aims.
The lambda will aim to what ever you set it - but it can only aim so much.
If the fuel factor table (10x10 fuel side) map is not altered correctly and the fuel scaling factor is not calculated correctly with respect to the size of the injectors then the aim will always be aiming but never achieving because the deviation is simply too large.
Our own supercharged car has been tested in 0 degC, 5-8 degC and 25+ degC. Our aim is 12.2 AFR. We achieve very close to it what ever the ambient temperature is (there is a limit where physics will take over but they are big). The reason is because the fuel scaling and fuel factor table has been correctly set which is derived from continual testing and retesting.
Now, for the fueling to go leaner with colder denser air implies that the DME is infact not at all intelligent and is like that of a Bosch Motronic 1.1!
A denser cooler charge will actual require more fuel and if that did happen then the AFR will be maintained.... like we would hope.
An intelligent DME will not allow this unless the base calibration for fuel is too far out for the aim to reach as mentioned above.
It's all quite logical.
I am by the way not going to comment on if the AFR is lean or rich on any graphs. Who knows... could be down to placement of the probe. Could be a break in the pipe drawing in air? Who knows?
(opens packet of silk cut silver and begins to smoke)